In the past it has been thought that it is necessary for a rake to rotate in order to lift thatch, such as grass cuttings and other debris from its position on the surface of the ground beneath a grass lawn.
The thatch is so firmly embedded in the grass and so thick and compact in most cases that an ordinary forward motion raking action with stiff rake time, such as used in a common garden rake, tends to damage the roots of the grass because of the stiffness of the tines. The common stiff hand rake, when pulled forwardly across the surface of the ground, only claws, and does not lift the thatch. The result is that such a rake just becomes clogged with thatch, and quickly needs to be manually cleaned, and this leads to tedious labor.
For this reason power rakes have become popular. Power rakes have a rotary motion and, therefore, have the possibility of lifting the thatch. However, the power rake also has the tendency to rip up the roots of the grass. Much destruction is caused. Rotating power rakes do not follow the terrain. Therefore, when they come to ground which is slightly higher the grass roots are more severely ripped out.
Such rotating power rakes require considerable skill on the part of the operator because the power rotation tends to propel the rake forwardly, and much attention needs to be given to hold the rack back and to guide it. This makes a very tiring operation if a lawn has much size.
Rotating power rakes for the lawn have appeared to be no more than an adaptation of rotating power rakes used for hay in farm work. The chief difference has only been in size of the units.
I am aware that a lawn thatch removal rake was proposed in U.S. Pat. No. 3,765,159 issued Oct. 16, 1973 to Dean O. Neff, and titled: "Thatch Removal Device." In the said patent the teeth are designed to dump clumps of thatch collected thereon rearwardly of each tooth as the pressure of the thatch built up against its forward side causes that tooth to spring upwardly and rearwardly sufficient to allow the clump of thatch to pass thereunder.
All of this is because the teeth in the patent to Neff U.S. Pat. No. 3,765,159 incline rearwardly at times when they are in rest position.
The tines of the said patent necessarily incline rearwardly from the vertical at times when they are in rest position. They also incline rearwardly from the vertical at all times since they cannot come forward beyond the vertical because the ground surface would prevent that.
It is an object of this invention to provide my new concept of having tines which incline forwardly of the vertical when in rest position and which are so mounted that they tend to dance back and forth and from side to side. My tines, on forward motion, tend to pitch the thatch forwardly and upwardly much like the tines of a pitchfork would. That way they surely lift the thatch out of the ground, and yet the speed of vibration is such that my tines are constantly self cleaning. They are almost immediately pitching thatch upward before they can become loaded to an extent that would render them non-functional because of a clump of thatch. The clumps of thatch simply do not form, because the forward and upward pitching is sufficiently rapid.
Another objective of this invention is to provide a tine so positioned in moving that it is always in good working order, never clogged by thatch.
Another object is to have the rake supported on multiple rows of tines so that it follows the level of the ground and does not tend to dig in excessively deep in places of gradually increasing ground height.
Self-cleaning of the tines is another objective and is accomplished by having multiple rows of tines so that clumps of thatch can be passed by without being hung up as they would be if all the teeth were in one single row of extremely closely spaced teeth.
A further object is to have the lowermost ends of the teeth of the multiple rows spaced gradually higher at the forward, and gradually lower at the rearward rows, so that the teeth in the forward rows which would naturally catch the most thatch do not do all the work by tending to lift the frame until the rearward rows are out of raking position. By having the rearward rows gradually lower, they will still be effective, and the forward rows will not do such a large proportional amount of the raking.
Disposing of the rows in this position is a function of the length of the tongue, the angle of attachment of the tongue to the rake frame and the height of the forward end of the tongue during towing.
An objective is to provide a rake capable of being towed by a common self-propelled riding lawnmower of modest size.
An important objective is that the teeth be designed to pitch the thatch upwardly and forwardly into good position for removal by a power lawnmower or a lawn broom.
The downward pressure of the rake is regulated by placing various weights thereon to deal with the conditions of whether the grass is wet of dry or the ground is moist or dry, or whether cultivation or raking is desired.
The cultivation of row crops is an objective and is achieved through the concept of holding some of the tines upwardly so as to permit part of the rake to not be in operation so that that part of the rake can be disposed over a row crop.
A further objective is to provide a tooth stiffening horizontal member having openings therethrough, each receiving a mid-section of a tooth, such a member being secured to the frame for stiffening the teeth for use during light tillage such as grass seeding or lawn re-seeding. The peg board is not used during row crop cultivation, nor during ordinary use as a thatch rake.
In general, the new lawn rake and cultivator has four major functions: (1) Use as a lawn rake to remove thatch and debris; (2) For seed bed preparation for garden or grass seed; (3) To prepare a lawn by very light tillage, such as to over seed by preparing a shallow seed bed in a present lawn with the tines stiffened with the stiffener member, whereby seed is worked into a present lawn; and (4) Use as a garden cultivator.